1. Field of the Invention
This invention relates generally to the field of pushbutton radio tuners with manual controls, and specifically to an improved manual tuning drive gear assembly with adjustable front panel positions.
2. Prior Art
In the prior art, various types of apparatus have been used to allow the front panel position of the tuning shaft control to be adjustable. Adjustment of the tuning control front panel position using these prior art methods usually resulted in the pinion gear, which was connected to the control shaft by a universal coupling, being misaligned with the crown gear being driven. This was due to the fact that the axis of the pinion gear was not in radial alignment with the crown gear. This misalignment of the gears caused cross-cutting and binding between the teeth of the pinion gear and the crown gear.
Some of the prior art attempted to solve the misalignment problem by having a bracket support the shaft to which the pinion gear was connected with the pinion gear shaft being adjustable over a range of positions. These brackets still did not maintain the axis of the pinion gear in radial alignment with the crown gear and involved use of a relatively complicated support bracket.
An improved assembly for adjusting the position of the control shaft while maintaining the axis of the pinion gear in radial alignment with the crown gear was described in the patent to Gordon, U.S. Pat. No. 3,964,320, patented June 22, 1976, assigned to the assignee of the present invention. That invention used a pinion gear support bracket which maintained the pinion gear in radial alignment with the crown gear. The support bracket in that patent must be manually adjusted for each desired position. It is advantageous to have the pinion gear automatically radially aligned with the crown gear no matter what position the control shaft is placed in on the front panel.